Dr. Conrad Murray made his first mistake when he signed on to be Michael Jackson’s personal physician.

Perhaps the task was doomed for any doctor, but Murray was particularly ill equipped to deal with the King of Pop’s concoction of quirks and cravings. Murray was operating well outside of his training, and this gives prosecutors their first plank in building a motive. Murray didn’t care about Jackson as a patient, they will say. He only wanted that $1.5 million pay check.

Murray is licensed to practice medicine in Nevada, where he apparently met Jackson, in Texas and in California, where the singer died in Murray’s care. Murray has denied all wrongdoing in Jackson’s death.

He was trained in cardiolgy, although he was not board-certified in cardiology. And by the time he was treating Jackson, he had let his board certification in internal medicine lapse.

He did have a sleeping problem. And, by many accounts, he had a painkiller addiction so severe that he was using aliases to get access to more drugs.

He needed a pain specialist, someone with specific training in treating patients with a variety of options and weaning them off addictive drugs. Typically that means a board-certified anesthesiologist who specializes in pain medicine. The American Board of Medical Specialties recognizes one board for pain medicine credentialing: the American Board of Anesthesiologists.

Murray, needless to say, did not have pain medicine credentials.

You can almost hear the prosecutor’s questions to Murray, should he take the stand.

Prosecutor: Where did you go through your residency in anesthesiology?

Murray: Nowhere.

Prosecutor: But you were administering an anesthetic, correct?

Murray: Correct.

Prosecutor: You say you were trying to help Jackson sleep because he was in pain. When did you take your fellowship in pain medicine?

Murray: Could you repeat the question?

Prosecutor: That’s OK. How about this one. How many patients did you treat for chronic pain conditions before you agreed to treat Mr. Jackson?

Murray: Well, I would have to go back to my files …

Without training or board certification in anesthesia or pain medicine, Murray started giving Jackson heavy doses of anesthetics, anxiety pills and sleep aids, any one of which could have killed him.

This was on top of other drugs prescribed by other doctors and whatever other drugs Jackson was taking that he had procured elsewhere. Investigators also found the muscle relaxers zanaflex, clonazepam and tizanidine; the anesthetics propofol and midazolam; the anti-depressant trazadone; and various allergy drugs and antibiotics. Perhaps it’s no surprise that they also found flumazenil, which is commonly used to treat overdoses.

The drugs were in plain view in Jackson’s home, so there is no excuse for Murray to not know what his patient was taking and how a combination of certain drugs might be lethal. When he was administering the propofol, he should have taken into account everything in Jackson’s system that might interact with it badly.

This was on top of other drugs prescribed by two other doctors and whatever other drugs Jackson was taking that he had procured elsewhere.

The drugs were in plain view in Jackson’s home, so there is no excuse for Murray to not know what his patient was taking and how a combination of certain drugs might be lethal. He also has admitted administering the propofol.

This is what can happen when a physician strays this far outside of his expertise. Murray is going to have a tough time explaining what exactly he thought he was doing and why he thought he was qualified to do it.